This IS a ripoff -- it's not that much cheaper than the full package, and is missing two figures that normally sell for around $10 each. Collecting the figures is a big part of what kids love about the game, plus having more figures adds more variety and replayability, so this package seems pointless to me. I don't understand why it doesn't include the same three figures.
On another note (I can only speak for the PS3 version here -- the DS version may differ), the original Skylanders portal was wireless. It needed batteries and a very tiny USB dongle that is easy to lose. The portal that comes with Giants is wired -- no batteries and no dongle to lose. The wire is plenty long, too. So that's another good reason to get the full package.